Heat motor



Feb. 21, 1939.

' G. R. FOLDS HEAT MOTOR Original Fild April 25,

1952 3 Sheets-Sheet 1 F m R. w m w G G. R. FOLDS Feb. 21, 1939.

HEAT MOTOR Original Filed April 23, 1932 3 Sheets-Sheet 2 George [bio/s,

Feb. 21, 1939. v G R, FOLDS 2,147,695

HEAT MOTOR Original Filed April 23, 1952 3 Sheets-Sheet 3 [n venzor;

A Gewye R. Folds wig i8.

Patented Feb. 21, 1939 HEAT MOTOR George it. Folds, Chicago, 111.,assignor to Cook Electric Company, Chicago, 111., a corporation ofOriginal application April 23, 1932, SeriaLNo.

607,934, now Patent No. 1,996,237, dated April 2, 1935. Divided and thisapplication May 18, 1934, Serial No. 726,206

Patent Number 1,996,237 on April 2, 1935.

Usually, in heating systems for homes or the like, a damper controlleris employed to actuate the draft and check dampers of the heater, and,

in the case of oil or gas furnaces, the controller is arranged toconnect with a valve controlling the flow of oil or gas, and, in certaininstances, also with the air supply supporting combustion.

Where the controller is electrically operated, the

circuit is connected to athermostat responsive to room temperature sothat the rate of combustlon may be increased until the fire is broughtjto a point of supplying heat sufficient to. satisfy the room thermostat.I find, however, that the temperature of the furnace increases to suchan extent that the furnace necessarily continues to supply heat beyondthe requirements of the room thermostat before the combustion can bechecked. This results in what is known as periodic overshooting of thefurnace and causes uneven heating of the room which is undesirable andresults in waste of fuel and considerable annoyance.

An object of the invention is to provide a furnace control, which, whenthe room thermostat calls for heat, will increase the rate of combustionuntil the furnace temperature reaches a predetermined degree and willthereafter decrease the rate of combustion without checking thecombustion until the room thermostat is satisfied.

A further object of. the invention is tO DIO- vide an improved form offurnace control having a valve or damper controller connected to theroomthermostat and to the furnace, adapted to operatenot only inaccordance with the requirements of the room thermostat, but also orother thermostat, wherebythe combustion is temporarily decreased butnotcompletely checked, so that the-continued decreased combustion willsupply only that heat which is required to satisfy the room thermostat.Accordingly, the furnace will not continue to supply heat after the roomthermostat is satisfied to cause an uncomfortable temperature and anunnecessarywaste of fuel.

Many other objects and advantages of the invention will be apparent fromthe following dein accordance with the requirements of a furnace (Cl. co-25; Y

tailed description when taken in connection with the accompanyingdrawings which form a part hereof.

In the drawings:

Figure 1 is a view illustrating a furnace or heater with control,apparatus embodying my invention applied thereto;

Flg. 2 is a side elevation, with the cover and housing in sectionremoved, of one form of damper controller that maybe used;

Fig.8 is a wiring diagram illustrating the apparatus connected incircuit with a thermostat. responsive to temperature of the room orrooms to be heated; Y

Fig. 4 is a similar view illustrating an alterna- A tive form ofelectrical connections for the control apparatus;

Fig. 5 is an enlarged vertical section of the heat motor of ,the' dampercontroller shown in Figs. 2' and 3;

Fig. 6 is a similarview of the alternative form of heat motor shown inFig. 4; and

Figs. 7 to 10, inclusive, are vertical sectional views of the heatmotor, but omitting the lower portion, whereby to illustrate structureeflecting a quick return of the volatile fluid into the tube after theheat has been discontinued.

To illustrate one possible embodiment of the invention, I have shown inFig; 1 a furnace 4 having the usual air inlet damper 2 'and the checkdamper 3, but it will be understood that inso far as the disclosure ofthe invention is concerned, the illustration is merely conventionalinasmuch as the invention is capable of wide application and may be usedto control elements other than dampers, such as gas valves, steam andhot water valves, or devices other than those in heating systems. Thefloor of a room to be heated is indicated at5 and a thermostat 6 islocated within the room. A damper controller 1,

which may be electrically operated or otherwise,

and whichmay be of common commercial form, v

such as is described and claimed in United States Letters Patent'No.1,962,292, granted June 12,

1934, to John S. Baker and assigned tothe as- 'signee of the presentapplication, is connected by means of a chain 9 to draft damper 2 and bymeans of a chain In to check damper 3, there being a damper arm 8connecting these'chains to the controller. Damper controller 1 isadapted to increase the rate of combustion by moving chains S-and I0 toopen draft damper 2 and to close check damper 3 when electric current issupplied to the controller by actuation of room thermostat 6. when nocurrent is supplied, the

controller operates to check combustion by moving the chains in oppositedirection.

.A push button ii is provided to disconnect the drive between dampercontroller 1 and arm 3 to allow independent operation of dampers 2 and 3during flring of the furnace, or for any other purpose. It will beunderstood that damper controller 1 may have any suitable form of motorfor driving damper lever 3 to operate dampers 2 and 3.

For purposes of illustration, I have shown in Fig. 2 a heat motor Iihaving an expansible chamber l2 provided with a movable wall i3connected to a power arm l4. Arm l4 may be connected-to damper lever 3by a clutch designated generally as Ii, which clutch, when operated bypush button II, will disconnect the drive of motor ii to permitindependent operationof dampers 2 and 3.

A detailed description of clutch mechanism l5 and the manner in whichpush button ii is arranged to disconnect the drive between motor l3 anddamper lever 3' is given in said United States Letters Patent ,No.1,962,292, and, consequently, it is deemed unnecessary for a clearunderstanding of this invention to describe this mechanism more fully.

Heat motor I3 is provided with a pair of heating tubes i1 and 33, bothin' communication with chamber I2 and both adapted to receive a volatile substance which extends upwardly into these tubes from chamber l2.A portion or all of the volatile substance in these tubes l1 and 33ismains being represented at 25.

Tube :0 has its resistance wire u connected between upper and lowerterminals 32 and 33. Upper terminal 32 is connected by a wire 34 and bywire 23 to transformer 24. Lower terminal 33,

is connected by a wire 35, a switch 33, and a wire 31, to say wire 23 ofthe opposite side of the circuit. Switch 33 may be thermostaticallycontrolled and may be responsive to the temperature of furnace 4.

Assuming that room thermostat 6 is calling for heat due to a drop intemperature, current will flow from transformer 24 through wire 23,thermostat 3, wire 23, heat coil or resistance wire l3, wire 22, wire 23and back to transformer 24. Current /will also flow from one side ofthecircuit, say from wire 23 through wire 31, switch 33, wire35, heat coil3|, wire 34 and back to the other side of thecircuit, say wire23. Theheat effects produced by this current flow through resistance wires 43and 3| will vaporize a portion or all of the volatile fluid in tubes l1and 30, depressing the level of the unvaporized fluid below the heatingzone and expanding chamber l2, thereby driving power arm |4..downwardlyto swing lever 3 clockwise. This action of lever 3' operates, say in theembodiment shown in Fig. l, to open draft damper 2 and to closecheckdamper 3. The reverse movement of dampers 2 and 3 occurs when theincreased combustion in the furnace 4 produces suflicient heat tosatisfy the demands of room thermostat 3. 1

accomplished in various ways.

To prevent the heat of furnace 4 from overshooting the -room temperaturedemanded by thermostat 3, switch 36 is arranged to open the circuit upona predetermined rise in temperature of the furnace, which furnacetemperature is suiiicient upon the opening of thermostat 36 to continuefurnishing the heat required to satisfy the room thermostat. The currentwilldiscontinue flowing through the circuit of switch 36, and tube willcool to condense the vapor therein and reduce the pressure so that thisvolatile fluid'may again rise in the tube 33 to allow expansible chamber|2 to contract, s'ay, half-way, or any portion of its stroke, asindicated by line b in Fig. 5, in order to swing lever 8counterclockwise midway or so of its position, depending upon theadjustment desired, between its on and off position whereby to partlyclose draft damper 2 and slightly open check damper 3, if so desired.Itwill bemnderstood that the extent of the return movement of lever 3 toalter the closing positionpf the dampers at this point in the operationof the heater may be predetermined by the capacity of. tube 30 withrespect to the combined capacities of. both tubes. This actionmaybearranged to allow draft damper 2 to close half way or any. otherfraction of its completely opened position, if so desired, and likewise,to alter the position of the check damper 3 if so desired. 1

Furthermore, any number of, tubes similar to tubes I1 and 30' maybeprovided. These tubes may be under the control of different circuitshaving one or moreswitches similar to switch 33 so as to vary the degreeof closing movement in accordance with the desired continued combustionof furnace '4 after a predetermined fur nace temperature is reached toprevent overshooting this furnace temperature as demanded by thermostat6 whereby to provide a relatively constant room temperature at alltimes. Moreover, switches 36 may be actuated according to conditionsother than furnace temperatures, and may be inserted in control circuitsfor governing the operation of one or more devices.

After the circuit of switch 36 is opened and draft damper 2 slightlyclosed, the rate of combustion of the flre will be decreased butthecomthe circuit of thermostat 6 is opened. When thermostat 3 opens,tube I'I will cool to condense the vapor and totally relieve thevolatile fluid in chamber |2 of vapor pressure so as to allow a portionof the volatile fluid to'return in tube I1 and bring-lever 8 clockwiseto its off position.

As stated above, checking the increased rate of combustion after apredetermined furnace temperature is obtained to prevent overshooting ofthe furnace by the continued combustion of the fire until roomthermostat 3 opens, may be There is illustrated in Fig. 4 heat motor 3provided with a heating tube 40 having a single resistance wire or heatcoil 4| about this tube, but so connected to the circuit of roomthermostat 6 and the cir-' edit of switch 33 that after the lattercircuit is opened, the heat produced by the current flow through heatcoil 4| is reduced sufllciently to allow a return of the volatilesubstance a part of the way upwardly in this tube in order to returnlever 3 to any desired position to alter the open position of, draftdamper 2, and, if so desired.

the check damper 3, or valves if employed. This is accomplished byconnecting the circuit of' room thermostat 3 to a predetermined numberof turns of the upper portion of the heat coil so as to limit theheating zone of tube by .the current flowing through the circuit ,ofroom thermostat 6. The circuit'of switch 36 is connected to theremaining turns of the lower portion of the heat coil that when currentflows through this circuit all the volatile fluid in tube 40 will bevaporized and held depressed in chamber l2 to keep'the lever 8 atitsfull on position. This arrangement is obtained by connecting wire 20of room thermostat circuit to the upper terminal of resistance coil 4|and wire 23 to an intermediate turn of this resistance coil. Wire 35 ofthe circuit of switch 36 is connected to theldwer terminal, the wire 23forming a common return for both circuits. It is obvious, therefore,that the result of returning damper .lever B to any intermediateposition after the furnacetemperature reaches a predetermined degree maybe obtained in various ways, and consequently, I do not intend beinglimited to the specific structures shown. r e

InFig. 5, I have illustrated heat motor I6 with resistance coils i8 and3| of tubes l1 and 30 connected in separate circuits, but with the samereference characters illustrating corresponding parts in each circuit.The showing in-Fig. 5.

in and fill tube i'l, thereby allowing the vessel to return a furtherdistance equal to character a. If itis desired to vary the outwardstroke of power arm i4, instead of the return stroke, switch 6 may bearranged to close before or after switch 38. I consider such variationsas withinthescope of this invention. On the other hand, if it is dersirable for any reason whatever to vary the time of action of the heater30 with respect to the time when the heater l1 should function, byvarying the heat input through varying the how of current, an adjustableresistance 45 may be inserted in either control circuit, or specificallyas shown in the control circuit having the switch 36.-

In a similar manner, Fig. 6 illustrates the distances the wall 13 willexpand or contract when the current flows throughthevarious sections ofresistance coil 4! of tube 40 and is controlled by switches 6 and 36.For. the purposes of illustration, the switches 6 and 36 have been shownin Fig. 6 as incorporated in separate control circuits, but it will beunderstood that the circuit arrangement may be the same as shown in Fig.4.

The foregoing description gives a clear understanding of at least oneembodiment of the invention. 0n the other'hand, the advantage of thistype of heat motor will also be readily understood in connection withvarious types I of systems wherein switch 38 might be located in adiiierent zone than switch 6. To illustrate, outside temperaturevariations may, be utilized to operate switch 36 so that a drop inoutside temperature will close switch 36 and operate motor l6 -where-'by to swing lever 8 a distance proportional to the "movement of themotor, which distance is represented say by line 1 in Figs. 5 and 6..The motor will be held at this position as long as the outsidetemperatureremains low. Depending upbn the type of heating system, thedraft damper or valve will be in a partially open position to keep thefurnace at a higher temperature, and the.

room thermostat 6 will thereafter function to provide such additionalcombustion as will furnish the desired uniform or constant temperaturein the room. Moreover, the switch 38 may be located in the same room asthe thermostat i, but at a location most apt to be influenced by outsidetemperature changes, or drafts, say at the base board, or below thestool of a window.

It must be understood that although damper 2 and 3 are shown as the heatcontrolelements of the furnace 4, by similarly applying-the ap paratusto the fuel supply system of an oil or gas-fired furnace, the same maybe controlled exactly in the same manner. The term damper controller is,therefore, intended also to refer to a controller capable of being usedwith oil or gasflred furnaces, or for operating any type of'valve in aheating system,-or other system controlled in accordance with a variableoperating condition.

Figs. 5 and 6 illustrate in cross section the interior construction ofthe heaters and the manner} "of connecting the tubes to the outer wallof the expansible and contractible chamber. The lower end of the tube istapered at 46, the end 41 enteringan opening 48 in the outer wall. A jet49 constructed in,the form of a conically shaped nipple is inserted inthe lowerz end 41 of. tapered end 46 and connected thereto by means of aflange 50 and a soldering connection 5 I A- second solder.-

.rapidly into contact with the upper wall of the tube. I find that thisspraying action of the volatile fluid, which is effected by jet 49,reduces the time required to cool the tube and effects a return of themotor substantially in one-sixth of the time required heretofore in the.return of the fluid when the Jet 49 was not employed.

Figures '7 to 10, inclusive, illustrate approximately the manner thevolatile fluid is returned into the tube by the jet 49.- When the flowof current through the resistancecoil is discontinued by the opening ofthe switch, which may be in the circuit controlling the flow of current,the upper walls of the tube will cool. At least a portion of the vaporsin the tube which holds the unvaporized fluid in chamber l2 willcondense and thereby destroy the pressure balance between the vapor inthe tube and the pressure in chamber l2. After the initial coolingaction, which effects initial condensation and drop of pressure, aslight bubbling or spraying of the volatile fluid through.

spray stream in the tube to the positions shown in Figs. 8 and 9, butthe change is by a spurting l action of the stream from one sprayingposition to the other, which spurting action is rapid and causes a quickcondensation of the vapor in the tube. This quick condensation not onlyshortens the time: of the return stroke of the motor, but it permits "ofa quick action which is quite valuable in many cases, such as operationof certain types of gas valves.

The time action of the spraying has been found to be relatively fast,and so much so that by the time the spray takes the form shown in Fig.10, wherein the volatile fluid is being sprayed directly against theupper end of the tube, only enough volatilefiuid has been returned intothe tube to result in the liquid level shown in this Fig. 10, whichliquid level is at that time slightly above the orifice 52. The fluidwill be sprayed, however, through any liquid extending over the orifice53, as shown in Fig. 10.

From experiments I have found that the heat motor will contract oraccomplish its return stroke within 25 to seconds,as compared to theformerly required time of three minutes. This time may vary somewhat,however, with vessels of different sizes and capacities. Although theexpansible and contractible wall I3 is shown in the drawings asexpanding on the return stroke, it is to be understood that the reverseaction in the operation of this wall may be used, as illustrated inUnited States Letters Patent Number 1,885,285 granted November 1, 1932,to Lawrence M. Persons and assigned to the assignee of the presentapplication. Moreover, it will be understood that the above explanationof the action of the fluid returning into the tube is the result of myobservations -during certain operations 1 have conducted, but,notwithstanding, I do not intend to be limited to this action. Theinvention is directed more broadly to the purpose of eflecting a rapidcooling in considerably less time. The same result might obviously beobtained by a slight rearrangement of parts which would be within thecontemplated scope of the invention. Variations in the details of thetube arrangement and heating means may be likewise employed withoutdeparting from the invention.

From the foregoing description of the invention, it will be apparentthat the invention is directed to a new and improved form oiimotor shownand described in my aforesaid copending application, Serial Number607,034, of which the present case is a division. Basically, the motoris capable of wide adaptation and can be used in various ways. For thepurposes of. apprising those skilled in the art of the manner in whichthe motor may be widely adapted, I have referred herein to severalapplications only, andnot to each and every application thus far made byme, which, it is quite apparent, will be unnecessary to obtain a clearunderstanding of the invention, and of its purposes and principles ofoperation, in view of the explanation and description of the embodimentsherein given as clearly illustrative of its broad field of use. Themotor may be obviously used to operate dampers, valves, switches, or anyother element or in any system requiring a prime mover.

Without further elaboration, the foregoing will so fully explain thegist of my invention that others may, by applying current knowledge,readily adopt the same for use under varying conditions of service,without eliminating certain features which may properly be said toconstitute the essential items of novelty involved, which items areintended to be defined and secured to me by the following claims.

I claim:

1. A heat motor comprising, in combination, an

expansible and contractible vessel and a plurality of substantiallyclosed tubes in communication with said vessel, a volatile fluid in saidvessel and said tubes; and means for displacing the fluid from one orboth of said tubes into said vessel to produce a working strokeproportionate to said fluid displacement from one or both of said tubescomprising a heat coil for each tube providing a heating zone for thevolatile fluid therein, and a circuit for each heat coil effecting aflow of current simultaneously through both or singly through one ofsaid heat coils whereby to displace the fluid from both or one of saidtubes into said vessel.

2. A heat motor comprising, in combination, an expansible andcontractible vessel and a pinrality of tubes in communication with saidvessel, a volatile fluid in said vessel and said tubes, and means fordisplacing the fiuid from one or both of said tubes into said vessel toproduce a 'working stroke proportionate to said fluid displacement fromone or both tubes comprising a separately controllable source of heatfor each tube providing a heating zone for the fluid therein whereby tocreate a pressure by vaporization of a portion of the fluid and adisplacement into said vessel of the unvolatilized fluid from one orboth of saidtubes.

3. A heat motor comprising, in combination, an expansible andcontractible vessel and a pluralityof substantially closed chambers incommunication with said vessel, a volatile fluid in said vessel and saidchambers, and means for displacing the fiuid from one or both of saidchambers into said vessel to produce a working stroke proportionate tosaid fluid displacement from one or both chambers comprising aresistance associated with each chamber and a source of electric energyin circuit with each resistance to provide a heating zone for the fluidin each chamber, and means for connecting one or both of saidresistances in circuit with said source whereby to displace the fluidfrom one or both of said chambers into said vessel.

'4, A heat motor comprising, in combination, an expansibleandcontractible vessel and a plurality of substantially closed chambers incommunication with said vessel, a volatile fluid in said vessel and saidchambers, and means for displacing the fluid in either or both of saidchambers into said vessel to produce a working stroke proportionate tosaid fluid displacement from either or both of said chambers comprisinga source of heat providing a heating zone for the fluid in each chamber,including connections associated therewith whereby to create a pressureby vaporization of a portion of the fluid and a displacement into saidvessel of the unvolatilized fluid from either or both of said chambers.

5. A heat motor comprising, in combination, a work chamber, a heatingchamber, and a fluid in said chambers whereby to form a closed fluidfilled system, a work performing connection for said work chamber andadapted to do work in response to changes in pressure in saidv workchamber, means for creating a pressure in said heating chamber andconsequently in said work chamber, and means associated with said firstvolatile fluid, and apparatus controlling the current flow througheither or both of said heat coils to expand said chamber and producepredetermined working strokes according to the number of heat coilsenergized.

GEORGE n. rows.

